This invention relates to an optical fiber interconnection system and, more particularly, to an apparatus and method for finding both ends of an optical cable whose ends terminate at different locations.
The growth in optical communications has been fueled by the extraordinary bandwidth that is available on optical fiber. Such bandwidth enables thousands of telephone conversations and television channels to be transmitted simultaneously over a hair-thin fiber that is made from a high-quality glass material. Nevertheless, bandwidth alone cannot satisfy some very simple needs that are easily handled by electrical cables. For example, electrical signals are the only practical way to interact with the existing communications infrastructure (e.g., standard telephone equipment) or even to operate a simple indicator lamp. And so it seems likely that the most desirable cables will combine electrical wires and optical fibers to enable designers to take maximum advantage of the strengths of each media. And while hybrid (i.e., electrical/optical) cables exist, hardware for connecting such cables to other communication equipment is presently too large, too costly or too cumbersome.
For example, patch panels are used to interconnect specific customers and equipment with other specific customers and equipment, and it is imperative that the connections be made accurately. One system is shown in U.S. Pat. No. 5,394,503, which discloses an optical fiber patch cable having end connectors that are arranged to operatively connect with patch panel couplings. Each patch cable includes one or more optical fibers and one or more electrical conductors. However, these end connectors and couplings are relatively bulky with large cross-section areas, each having many individual parts that do not yield to machine assembly. Consequently, they are neither space nor cost effective. Space is at a premium in such patch panels and an optical/electrical connector arrangement having a small footprint (i.e., cross-section area) is desirable, as is the ability to easily insert and remove closely spaced connectors in the patch panel; Moreover, the ""503 patent does not provide a craftsperson with an intuitive ability to identify opposite ends of the same cablexe2x80x94a simple task that calls for a simple solution. Instead, the ""503 patent uses a remotely located patch panel control system to identify cable termination pointsxe2x80x94a solution that is overly expensive and burdensome for the desired task.
Accordingly, what is desired is a system that provides reliable tracing of an optical cable whose ends are located at widely separated locations. Additionally, it is desirable that the tracing system be relatively intuitive to operate and not require special training.
The above-described deficiencies are overcome by a tracing system that enables a user to easily identify opposite ends of the same cable when the ends are installed in jack receptacles on different panels or on the same panel. The cable includes an optical fiber and a metallic wire, whereas the jack receptacle includes an optical port and an electrical port for interconnection with the cable. An electrical circuit is associated with the jack receptacle and it includes a manually operated switch and a light. The circuit makes electrical connection to the wire within the cable via the jack receptacle and a plug connector that is attached to the end of the cable. The manually operated switch has an active state and a normal state, and is configured to apply one voltage to the wire in its active state and to apply another voltage to the wire in its normal state.
In an illustrative embodiment, the cable extends between a pair of corresponding jack receptacles, each having the same electrical circuit associated therewith. Manually operating the switch associated with one receptacle causes the light associated with the corresponding receptacle at the other end of the cable to turn on. In another illustrative embodiment, manually operating the switch associated with one receptacle causes the lights associated with both corresponding receptacles to turn on.
In the illustrative embodiments, the cable includes a number of insulated wires that enable more sophisticated monitoring functions to be accomplished, which is of growing significance in view of the volume of data that can now be transported over a single optical fiber. Also in the illustrative embodiments, novel designs are shown for jack receptacles and plug connectors that accommodate optical and electrical transmission media. Panel mounting is advantageously simplified by molding a light-emitting diode into the receptacle itself to serve as the light and/or using a printed wiring board as the panel.